Improvement in circuits for automatic or chemical telegraphs



T. A. EDISON.

Circuits for Automatic or Ghemical Telegraphs.

N0. 141,772. .PatentedAugusti2,i873.

alum JW UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, OF NEWARK, NEWJERSEY.

IMPROVEMENT m cl ncul'rsron AUTOMATIC on cur men. TELEG'RAPHS.

Specification forming part of Letters Patent no. 141,712, dated August 12,1873; application filed- November 9, 1872.

licnlty by regulating the quantity of the cur-' rent passing to the chemical paper, and then bringing in an adjustable reverse current to neutralize any tailings.

1n the annexed diagram the peculiarity of arrangement of circuits and. instruments is illustrated.

A battery, (I, is connected through the transmitting instrument I: to the line-wire c, and the earth connection (I is of the usual character. At the receivlug-station the instrument cis to be of ordinary character for presenting the chemical paper to the action of the stylus and current. ltheostats have been used between the main-line and receivin instrumentand also in a shunt or branch circuit connected with the earth, and a battery has been placed in the shunt or branch circuit. I employ a rheostat', j, in a shunt connection between the parts'ot' the main line, through which a portion of the electric pulsation passes, the rheostat being sullicient to counteract the resistance of the chemical paper, and cause the proper proportion of current to pass through said paper. The battery h is placed in the main or branch line with its 'poles in a position to cause the electricity to circulate through the local circuit composed of 1, e, 2, f, and 3, in a direction opposite to that in the main line, so that anyattenuatiou ot' the mark may be prevented by the reverse action oft-he currents. If the before-mentioned parts only were employed, the local battery It might be suflicient to neutralize the electric pulsations in the main line. I therefore introduce a rheostat, l, between the poles of the battery 71, and the same should be variable or adjustable to allow the action of the battery It to be varied, and only so much of the reverse current directed through the local circuit and the chemical paper as will prevent the attenuation or tailing of the mark upon the chemical paper, leaving that marl: clear and distinct.

I claim as my invention- The rheostat 1 applied to the battery h in the local circuit to regulate the action thereof, in combination with the rheostat f in the branch circuit, and the receiving instrument in the main circuit, substantially as and for the purposes set forth.

Signed by me this 5th day of November,

. THOMASA. EDISON.

Witnesses:

GEO. T. PINCKNEY, CHAS. H. SMITH. 

